title: Investigation of PMD in direct-detection optical OFDM with zero padding.
abstract: We investigate the polarization-mode dispersion (PMD) effect of zero padding OFDM (ZP-OFDM) in direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) systems. We first study the conventional equalization method for ZP-OFDM. Then an equalization method based on sorted QR decomposition is proposed to further improve the performance. It is found that the performance improvement of ZP-OFDM is due to the frequency domain oversampling (FDO) induced inter-carrier interference (ICI). Numerical simulation results show that compared with cyclic prefix OFDM (CP-OFDM), ZP-OFDM has a significantly higher tolerance to PMD in DDO-OFDM systems when the channel spectral nulls occur at certain differential group delay (DGD) values.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Arokiaswami
authors.initials: A
authors.lastname: Alphones
authors.forename: Wen-De
authors.initials: WD
authors.lastname: Zhong
authors.forename: Changyuan
authors.initials: C
authors.lastname: Yu